What is the purpose of a transformer in an electrical system?

• A. To measure electrical usage.
• B. To protect circuits from surges.
• C. To convert AC to DC.
• D. To change voltage levels (step-up or step-down) for distribution or equipment.

Answer: (D)

Transformers change voltage levels in an electrical system. They work on mutual induction between the primary and secondary windings, so the voltage on the secondary is set by the turns ratio. This lets you step voltage up for efficient long-distance transmission or step it down to safe, usable levels for equipment and buildings. That ability to adjust voltage is what makes transformers essential for distribution and for powering devices at the correct voltage. They aren’t measuring devices (meters), they don’t inherently protect against surges (surge protection devices do that), and they don’t convert AC to DC (that’s done by rectifiers).